Ok, let's try something else:
What differs from a PW to a 3 iron?
Answer: ball position relative to
LOW POINT.
The good news here is that the low point is the same for all your clubs in the bag: it is located in front of your left shoulder.
So if you manage to hit it well with a PW and
REALLY go to low point, you should have the same success with a 3 iron.
Your lack of success with the 3 iron is maybe a good clue that you don't drive to low point: You can go away with it with a PW because you can make decent ball/turf contact without going to low point: it works in compressing the ball but you'll lose accuracy because you break the ideal geometry of the stroke.
But with a 3 iron this won't work.
As a swinger you probably wasn't paying much attention to low point because centrifugal force pulls everything out and send the club head to low point almost automatically (provided you keep you flat left wrist of course

)
But as a hitter you must make a real effort to go there.
Don't forget: driving DOWN is not enough, you must also go
OUT or you'll fail to find the correct low point!
Think crossline.
Maybe you already do all this good but you should check it anyway!
